Roof construction system

ABSTRACT

A construction plank is disclosed which can be assembled in contiguous, aligned relationship with other planks into a construction unit to form a building roof or other section. The individual planks are of varying geometric shapes and in the preferred embodiment are a composite construction having a structural core or panel member and an exterior sheathing member. A sheet of insulation may be included between the structural panel and exterior sheathing. Opposite edges of the plank are configured to complementarily engage the edges of similar planks in a lap joint to obtain flush assembly. Fasteners secure adjacent panels together at the complementary edge structures. In the preferred embodiment, the plank includes transverse straps extending across the panels which are fastenable to adjacent plank straps and underlying supporting structural members to pretension the straps to increase the lateral strength of the assembly against uplift resulting from wind. A membrane sheet is adhered to the exterior surface of the plank and includes a flap portion adapted to overlie the marginal portion of the next adjacent panel to provide a weatherized covering. The flaps are sealable by flexible interlocking fasteners carried on the sheet flap and marginal portions in the form of rib and groove elements. In the corner area between adjacent planks, overlying membrane flap portions are sealed by a mechanical fastener extending through the flap layers or by vulcanization. In another embodiment the flap edges are sealed by vulcanizing overlapping edges of the membrane sheets. In still another embodiment the plank is adapted as a fire resistant wall component having a suitable interior facing and a weatherized exterior covering.

United States Patent 1191 Simpson et al.

[ ROOF CONSTRUCTION SYSTEM [73] Assignee; Star Manufacturing Company,

' Oklahoma City, Okla.

22 Filed: 1 611.4, 1974 211 Appl. No.: 439,064

Related U.S. Application Data [62] Division of Ser. No. 336,370, Feb.27, 1973.

[52] US. Cl. 52/748 [51] Int. Cl. E04D 1/34 [58] Field of Search 52/748,81, 747, 543, 552, 52/540 [56] References Cited UNITED STATES PATENTS2,323,936 7/1943 Roberts 52/463 2,756,172 7/1956 Kidd 24 201 c 2,874,6522/1959 Wilson... 52/419 3,070,864 1/1963 Pfeffer 24 201 0 3,093,9356/1963 Dunn 52/309 3,254,459 6/1966 Bodley 52/81 3,373,537, 3/1968 1Blayden 52/288 3,455,076 7/1969 Clal'V06..... 5 2 309 3,468,086 9/1969Warner 1. 52/748 3,667,180 Tischuk 52/309 Primary ExaminerJohn E.Murtagh Attorney, Agent, or =FirmI-Iubbard, Thurman, Turner & TuckerOct. 28, 1975 [5 7] ABSTRACT A construction plank is disclosed which canbe assembled in contiguous, aligned relationship with other planks intoa construction unit to form a building roof or other section. Theindividual planks are of varying geometric shapes and in the preferredembodiment are a composite construction having a structural core orpanel member and an exterior sheathing member. A sheet of insulation maybe included between the structural panel and exterior sheathing.Opposite edges of the plank are configured to complementarily engage theedges of similar planks in a lap joint to obtain flush assembly.Fasteners secure adjacent panels together at the complementary edgestructures. In the preferred embodiment, the plank includes transversestraps extending across the panels which are fastenable to adjacentplank straps and underlying supporting structural members to pretensionthe straps to increase the lateral strength of the assembly againstuplift resulting from wind. A membrane sheet is adhered to the exteriorsurface of the plank and includes a flap portion adapted to overlie themarginal portion of the next adjacent panel to provide a weatherizedcovering. The flaps are sealable by flexible interlocking fastenerscarried on the sheet flap and marginal portions in the form of rib andgroove elements. In the corner area between adjacent planks, overlyingmembrane flap portions are sealed by a mechanical fastener extendingthrough the flap layers or by vulcanization. In another embodiment theflap edges are sealed by vulcanizing overlapping edges of the membranesheets. In

. still another embodiment the plank is adapted as a fire resistant wallcomponent having a suitable interior facing and a weatherized exteriorcovering.

9 Claims, 16 Drawing Figures L lllh 80 Q Ill/1"" US. Patent 0a. 28, 1975Sheet 1 of5 3,914,916

US Patent Oct. 28, 1975 Sheet 4 of5 3,914,916

ROOF CONSTRUCTION SYSTEM This is a division of application Ser. No.336,370, filed Feb. 27, 1973.

This invention relates to building construction and more particularlyrelates to a prefabricated building plank structure adapted for assemblywith similar planks to form a roof, wall or other construction section.

Conventional built-up roofing systems have been employed for many years.In this method of construction, a horizontal roof deck is supported onunderlying structural beams. The roof deck is covered by a weatherproofmembrane usually comprising alternate layers of felt and bitumen toprevent penetration of moisture into the building interior. The membraneis applied in a field operation by application of alternate layers ofhot bitumen and felt. Once the membrane is applied to the desiredthickness, gravel, rock or similar aggregate material is spread upon theroof to provide protection against weathering. To reduce heat transferthrough the roof deck, insulation is often applied to the underside ofthe roof deck at the interior of the building. Insulation may also beapplied on the exterior of the roof deck and subsequently covered withthe water resistant membrane.

There are many difficulties with built-up roof systems of the typedescribed above. Since the construction of the build-up roof is entirelya field operation, there is little uniformity of quality from onebuilding to another and consequently the integrity of such a roofstructure varies considerably. A built-up roof membrane has a tendencyto bubble and crack. This deterioration is due to a number of reasonsincluding expansion and contraction from severe temperature changes,moisture trapped below the water membrane and improper constructiontechniques. Further, built-up roofs do not withstand heavy foot trafficand are susceptible to damage from traffice. Also considerable safetyand environmental hazards exist in the application of hot tar whichoften gives off toxic fumes and polluting matter. Because of theundesirable nature of the hot tar process, local and federal safety andpollution standards often prohibit or restrict the use of built-upsystems which formerly had wide acceptance.

In an attempt to overcome the problems inherent in built-up roofingconstruction, it has been suggested to construct roofs of prefabricatedroofing panels. Roof panels of the prefabricated type generally includesome form of insulation such as a polystyrene or urethane foam andwallboard of asbestos or cement sandwiched together. A problem arises insealing the panel from the weather and water once the panels arearranged in a roof assembly. Often sealing is accomplished by placing amembrane similar to that used in a built-up roof over the roof panels.Obviously, such fabrication procedures require considerable field laborand do not avoid the shortcomings of built-up roofs.

In some instances, prefabricated roof panels have been formed with aweather resistant sheet material preadhered to the panels prior toinstallation. The preadhered sheet material may be coextensive with thepanel. In such a case an additional operation is required to seal theroofing panels at the joints as by use of a mastic or tape. It is alsoknown to provide the panel with a flap along one or several edges whichis adapted to overlie and is adhesively secured to an adjacent panel.However, such prior art prefabricating roofing construction has met withlimited success because of the manner of assembly and lack of integrityof the adhesively joined membrane sections. The prior art prefabricatedroofing construction panels generally require additional fieldoperations, such as application of insulating material to the undersideof the panel, to form a completed roofing structure. The unreliabilityof the prior art prefabricated structures along with the requirement ofadditional field work substantially adds to the cost of construction ofsuch panels.

In view of the above, there clearly exists in the building industry aneed for a prefabricated building plank adapted for assembly to form aconstruction section with provision for convenient, structurally soundconnection and sealing of the planks. The present invention providessuch a composite plank having an intermediate structural memberpreferably in the form of a corrugated sheet metal panel havinglongitudinally extending corrugations. A suitable interior sheeting suchas a wallboard is provided at one side of the corrugated panel. A layerof insulation and sheeting is provided at the opposite exterior side ofthe plank. The exterior sheeting may be a plywood or composite boardmaterial. A membrane of weatherproof material is bonded to the outersurface of the composite plank. The membrane is formed with a flap alongone or several edges which is adapted to overlie a marginal portion ofan adjacent panel. The membrane flap is adapted to sealingly engage themarginal portion of the next plank by vulcanization or by virtue'ofinterlocking fastener members cooperable with the flap and the marginalportion of the adjacent plank. The interlocking fastener may also takethe form of a mechanical clip or interengageable flexible rib and groovemember. The present invention further provides a corner seal to completean assembled structure. At the common juncture of several planks acondition exists .where several flaps overlie one another. A mechanicalfastener is used to compress the layers together at this juncture andseal the exterior surface of the membrane in the comer area.

A further aspect of the invention provides for assembly of a number ofplanks to form a roof having good longitudinal and lateral strength. Theindividual planks have opposite edge portions which are complementaryand which engage the edge of adjacent planks to form a lap joint withthe internal structural panel forming a part of the joint. When used asa roof or wall plank and when the plank must resist a load tending toseparate the plank from its structural support, an additional member inthe form of a transversely extending strap member is included to extendacross each plank and connect to an adjoining plank strap member and tothe supporting structural member. The straps are pretensioned to provideexcellent lateral strength to resist wind loadings that tend to lift theroof assembly.

The basic plank structure is also adaptable for use in construction offirewalls and other partitions. As a wall component the plank ismodified and is fabricated with a suitable interior facing such as avinyl or paper covering and has a suitable exterior weatherized coveringsuch as metal or simulated brick or stone. The planks are complementaryand can be assembled in interlocking fashion at their edges to form awall. Caulking or joint compound applied along the plank edges seals thestructure.

The plank of the present invention is a highly efficient structuralmember giving adequate support and resistance to imposed loads. Theplank can be factory assembled with a minimum of labor and a maximum ofquality control resulting in an economical product with minimum fieldmaintenance problems. The plank is highly versatile and can befabricated with varying characteristics to meet different requirementsof shape, strength, weight, thickness ratio, fire characteristics andthermal conductivity. Field installation is relatively simple usingmechanical fasteners and conventional bonding agents. The plank can beeasily altered in the field to meet special requirements by normaldrilling, sawing, screwing and cutting operations. As a roof or wallmember, the plank may incorporate the tension strap members as well as amembrane which is preadhered to each plank. The membrane is easilysealable at edge and corner portions to provide a tight, protectivecovering. As a firewall or other partition, the plank includes suitableexterior and interior coverings to eliminate the requirement for anyadditional finish work.

The above and additional objects and advantages of the present inventionwill become more apparent by reference to the following specification,claims and appended drawings in which:

FIG. 1 is a fragmentary perspective view illustrating the plank of thepresent invention as applied to the roof structure of a typicalbuilding;

FIG. 2 is an enlarged cross-sectional view of a portion of the structuretaken along lines 2-2 of FIG. 1;

FIG. 3 is an enlarged cross-sectional view taken along lines 3-3 of FIG.1;

FIG. 4 is a cross-sectional view taken along lines 44 of FIG. 1;

FIG. 5 is an enlarged fragmentary sectional view of a connection betweenadjacent roof panel members;

FIG. 6 is an enlarged sectional view showing in detail one of form ofthe connection between mating roof membrane sections;

FIG. 7 is a plan view of a single plank;

FIG. 8 is fragmentary sectional view showing an alternate method ofsealing adjacent membrane sections;

FIG. 9 is a sectional view of a mechanical clamp for securing adjacentmembrane sections;

FIG. 10 is a fragmentary plan view of a corner joint at the juncture ofadjacent panels;

FIG. 11 is a sectional view taken along lines l1ll of FIG. 10;

FIGS. 12 and 13 are sectional views showing alternate sealing structuresfor the corner joint;

FIG. 14 shows a cross-sectional view of another embodiment of thepresent invention adaptable for use as a firewall component;

FIG. 15 shows the joint between the wall planks of the embodiment ofFIG. 14; and

FIG. 16 shows a fragmentary perspective view of the connection of FIG.5.

Referring now to the drawings, FIG. 1 shows a roof assembly generallydesignated by the numeral 10 supported on an underlying supportgenerally designated 11 having a primary and secondary structure. Moreparticularly, the primary roof structure 11 includes transverselyextending beam or rafter members 12 which, as is known in the buildingart, are supported on columns or bearing walls. The secondary supportstructure includes longitudinally extending purlins l3 supported on theupper surface of rafters 12. The purlins are generlly Z-shaped havingupper horizontal flange member 14. The-primary and secondary roofsupport structure shown is for purposes of explanation only and, as willbe appreciated, forms no part of the present invention. It will beobvious to those skilled in the art that other supporting structurescould be similarly used.

The roof assembly 10 includes a plurality of individual planks 15. As isseen in FIG. 1, planks 15 are generally rectangular and adapted to spanseveral purlins 13. The geometric shape, however, may vary with thespecific requirements. The individual planks 15 are contiguously alignedin a side-by-side and end-to-end arrangement to form the roof structure10, abutting at common corner junctures 16. Roof planks 15 include anouter membrane sheet 20 of weather resistant sheet material preadheredto the exterior surface in a manner providing a pair of adjacent edgeportions or flaps 36 and 37 which extend beyond the corresponding plankedges and overlap the marginal portion of adjacent planks. At the cornerjuncture 16 of several planks, multiple layers of membrane overlay oneanother and are sealed at corner seal 21. The edge seal and corner sealarrangement will be explained in detail with reference to subsequentdrawing figures.

Referring additionally to FIGS. 2 through 7 which illustrate the detailsof construction of the plank sections 15, the individual plank sections15 are of a longitudinal composite structure having intermediatestructural panel member 24. Panel 24 is shown as a corrugated sheetmetal section having parallel upper surface 25 and lower surface 26formed by the laterally spaced, longitudinally extending corrugations 27in the panel. The particular cross-sectional shape and configuration ofcorrugations 27 is subject to wide variation as the panel serves as. thecore member of the composite plank 15 providing spacing and structuralsupport for the remaining members of the plank. Spacers 29, shown asgenerally rectangular members of plastic or wood, longitudinally extendalong the underside of corrugated panel 24. The depth of spacers 29approximately corresponds to the depth of the corrugations 27 in panel24 so that the bottom surface of the spacers 29 is coplanar with lowerpanel surface 26. Interior sheathing panel 30 is affixed to theunderside of corrugated panel 24 and to spacers 29. Preferably panel 30is a wallboard or plasterboard. A sheet of insulating material 32 isapplied across the upper surface 25 of panel 24. Insulating sheet 32 maybe a material such as ceramic, polystyrene or urethane foamed in placeor as a rigid panel. Exterior sheathing is provided by panel 34. Panel34 covers the upper surface of insulation 32 and provides a hard, smoothexterior surface. Panel 34 may be of a variety of materials and ispreferably a rigid panel of a composite hard board, plastic or plywood.Thus it will be seen that the core of the plank is a composite structurehaving an intermediate structural panel interposed between exterior andinterior sheathing panels. The core structure may be secured together byadhesives or bonding agents at the interface of the various layers or,as is shown, fasteners or staples 35 may extend through the core tosecure the various panel components of the structure together.

Other materials may be selected. For example, insulation layer 32 may bea foamed urethane of relatively low density covering panel 24. Panel 24may be formed in place by an application of a second layer of relativelydense urethane. The outer layer of dense urethane is suitable assheathing. This type of construction will speed production and eliminatethe need for adhesives or fasteners to secure the plank components intoa composite structure.

The basic plank or core structure is stronger than the individualcomponents because the sandwich construction serves to stabilize thecorrugated panel and increase the load carrying capacity. Theconstruction is relatively deep in cross section utilizing theinsulation material as a web so that the interior and exterior sheathingfunction similar to structural flanges. This results in increasedflexual strength and good deflection characteristics.

The upper surface of plank is covered with a sheet of membrane in theform of a weather resistant material to protect and seal the roof system10. Sheet 20 is substantially coextensive with the plank along adjacentlateral and longitudinal edges 43 and 41. Along the two oppositeadjacent edges, 40 and 42, a flap portion 37 and 36, respectively,extend laterally beyond the corresponding edge adjoining at corner 21adapted to overlie a marginal or selvage portion of the membrane on anadjacent plank. Membrane 20 is preferably a natural or synthetic rubberor plastic bonded or adhesively joined to the upper surface of upperpanel 34 and for example may be a material known under the tradenameI-Iypalon manufactured by the DuPont Chemical Company. Similarly, themembrane can be fabricated from a light gauge metal such as aluminum.

The opposite longitudinal edges 40 and 41 of adjacent planks arecomplementary and engage to form a lap joint when the planks areassembled in abutting engagement to form a construction unit or section.Edge 41 of the plank is formed having interior panel member 30 recessedlaterally inward of panel members 32 and 34. Opposite plank edge 40 iscomplementarily configured having inner panel member 30 projectinglaterally beyond upper panel members 32 and 34. A spacer member 28extends longitudinally along edge 40 centered below the terminal edgesof panels 32 and 34 to receive fastener members and to stiffen andreinforce the joint at the plank edges. When the edges 40 and 41 ofadjacent planks are abutted, a lap joint results, sometimes referred toas a ship lap joint At plank edge 41, corrugated panel 24 is formed witha horizontally extending section 48 terminating at edge 21. lnwardlyspaced from the outer end of section 48 is abutment or projection 49.Corrugation rib 50 extends laterally beyond the terminal edge panel 30at plank edge 41 and is connected to panel member 48 by diagonallyextending leg 51.

At plank edge 40, horizontal lip 53 of panel 24 projects beyond the edgeof panel 32. Member 54 extends diagonally between corrugated panelmember 53 and 55. The shoulder formed at the intersection of members 53and 54 corresponds to projection 49 on the opposite panel edge 40. Whenadjacent planks are placed in contiguous alignment with edges 40 and 41engaged, a joint is formed with opposite edge structures of corrugatedpanel 24 overlapping and reinforcing the joint. Projection 49 carried onpanel 24 engages opposite panel member 54 to regulate the depth ofrelative engagement between adjacent planks in an assembled position.

The plank assembly consisting of the individual planks 15 is secured atintervals along adjacent longitudinal panel edges 40 and 41 by fasteningmembers 60 which penetrate through lapped panel members 48 and 53 andinto reinforcing member 28. Member 28 stiffens the lap joint andprovides backup material for penetration by fastener 60. Fastener 60 isdisplaced laterally from the crevice between abutting exterior panels 34in a recess 61 provided in the edge of panel 41. Fastener 60 forconvenience is shown as a self-tapping metal screw but obviously may bein the form of a rivet, bolt or other means of mechanical fastener.

The opposite lateral edges or ends 42 and 43 of planks 15 are configuredto abut in a lap joint when panels are abutted end-to-end as seen inFIG. 4. Panel member 24 and interior member 30 are longitudinallyrecessed at edge 42. Opposite plank edge 43 is formed with members 32and 34 inwardly recessed. Flap portion 36 of membrane 20 projects beyondedge 42 to cover the joint formed between abutting panel sections andoverlap the marginal or selvage portion of the membrane of the adjacentplank. Preferably as seen in FIG. 4, the major portion of the interfaceof the shiplap joint between lateral ends of abutting panels directlyoverlies the flange 14 of purlin 13 to give support to the joint.

The lateral strength of the assembly 10 is reinforced by the inclusionof laterally extending tension members extending in parallel at spacedintervals across the planks. As seen in FIG. 1, the individual planksare of substantial length traversing several purlins. Preferably alateral tension member 70 in the form of one or more flexible straps isincluded in the plank at a position corresponding to location ofintermediate purlins. The detail of strap members 70 is best seen inFIGS. 3, 5 and 16. Strap members 70 extend laterally across the uppersurface of the panel 34 beneath membrane sheet 20. The opposite ends 71and 72 of straps 70 extend be yond the edges of the corresponding panel34. When planks 15 are placed in engagement, the strap ends 71 and 72are secured to corrugated panel 29 by an appropriate fastener such asself-tapping metal screw 74. Fastener 74 secures the strap ends 71 and72 and penetrates into the corrugated panel section 53 and reinforcingmember 28. FIG. 5 shows in phantom lines the position assumed by thestrap ends prior to being secured in place. Once the ends of the strapare secured in place, the fasteners 74 are tightened and the strap isplaced in tension or prestressed to resist upward loads on the planksuch as are induced by wind currents blowing across the upper surface ofthe roof plank causing reduced pressure at the roof surface. Recesses 75and 76 are provided at opposite longitudinal plank edges at a locationcorresponding to the strap ends to facilitate tensioning the strap andto locate the strap ends to obtain a proper distribution of forces andminimize excessive crushing of the panel edges. The use of the strapspermits assembly of the planks without the necessity of placingfasteners through surface of the individual planks.

A Z-section clip 78 is provided at the connection of strap ends toreinforce the connection. Clip 78 conforms in shape to corrugated panelsections 53 and 54 and has upper and lower flanges 77 and 79. As seen inFIGS. 5 and 15, clip 78 is interposed between the overlapping section ofpanel 24 with fastener 74 secured to flange 77 of the clip. A secondfastener extends through the the lower flange 79 of the clip 78 tyingthe strap ends through the clip to the flange 14 of subjacent purlin 13.If necessary, several longitudinally spaced fasteners 74 and 80 may beprovided in the clip flanges 77 and 78.

One or more spacers 65 are provided between the adjoining ends of thestraps and panel section 48. Spacers 65 are preferably a compressibleinsulative material. The strap ends 71 and 72 lay against the spacerswhich give support to start fastener 74 through the metal. As fastener74 penetrates the lapped panel sections, the spacer is compressed. Thecompressed spacer serves to minimize heat conductivity between straps70, panel 24, and supporting purlin 13 When the assembly is complete,each tension strap 70 is tied at opposite ends to purlin 13 and, underupward loadings caused by a reduced pressure at the roof surface fromwind, assumes the general shape of a catenary curve. The panel willcorrespondingly deflect slightly to assume a similar shape. Normalloadings due to weight are resisted in the roof supporting structure atthe purlins and rafters. The strap 70 is designed so the angle of thestraps over the corner of panel 34 minimizes compression over the panelwhile maintaining the shape of a catenary curve which gives transversestrength to the plank.

Tne tension straps 70 may be embedded within upper sheathing 34. Withcertain materials, the upper sheathing 34 may itself provide thefunction of laterally strengthening the plank where the sheathing hasadequate tensile strength characteristics. The sheathing could bedirectly tied to the supporting structure or could be tied to thesupporting structure through clips 78. Either way, the sheathing couldserve to distribute loadings across the panel to the supportingstructure so as to reduce the number of fasteners transverse of theplanks.

One form of a closure assembly for securing overlying flap portions 36and 37 to adjacent panels is shown in FIGS. 6 and 7. Closure assembly 85includes a member 86 formed on the underside of the edge of flaps 36 and37. Member 86 has downwardly projecting rib sections 91 extendingparallel to the respective panel edge. The spaced'apart rib portions 91define parallel extending grooves 92 in the underside of flap 36. Theopposite coacting member 88 of fastener 85 is provided in the uppersurface of membrane at a location on the selvage adjacent edges 41 and43. Fastener member 88 is similar to member 86 and comprises a parallelseries of upwardly projecting ribs 93 which define parallel grooves 94.The ribs and grooves of fastener sections 86 and 88 are adapted tointerlock when force is applied, for example, to member 86 forcing ribs91 into corresponding grooves 94. The coacting sections 86 and 88 arethus capable of being interlocked in zipper fashion to form a tightmechanical lock. Various configurations of the ribs and grooves aresuitable for the fastener arrangement. A preferred configuration of thisgeneral type of fastener is shown and described in US. Pat. No.3,373,464.

The flexible interlocking fastener 85 is particularly suitable forsecuring the membrane covering 20 over an assembly of the planks 15. The.entire closure 85 can be fabricated into the membrane as part of theplank at the factory. The coacting fastener portions 86 and 88 areweatherproof and waterproof when engaged. Sealing can be accomplished bythe workmen when the panels are assembled. No special equipment isrequired to seal the adjacentmembrane sections. Obviously an adhesive ora vulcanizing agent can be applied between the grooves and ribs at thetime of securing the membranes together to further ensure againstpenetration of moisture and seal the interior plank structure.

FIG. 8 shows an alternate form of the flap portions and of the membrane20. In this structure a plank flap section 36a is associated with thepanel and is adapted to be sealed to the adjacent panel membrane byvulcanization or application of an adhesive. Flaps 36a do not carry anintegral mechanical seal but are substantially flat and adapted to lapthe adjacent plank membrane. The material of the membrane is preferablya natural or synthetic rubber or a thermosetting resin whichcharacteristically is adaptable to vulcanization. Once the panels areassembled with flaps 36a overlying the adjacent panel, the membrane canbe sealed by application of heat along flaps 36a with heating unit 98which is a flat iron having appropriate temperature control. Followingapplication of heat, a pressure member 99, shown as a weighted roller,serves to compress the overlying membrane members together to ensure agood seal. The temperature applied at flaps 36a should be sufficient toat least partially melt the upper membrane so that the underlying layeris heated and bonded to the flap 36a. The flaps 36a can also be adheredto the surface of adjacent panels by use of a suitable bonding agent oradhesive with or without the application of heat. vulcanization can alsobe carried out by use of sonic, electromagnetic or heat waves to causemolecular bonding when the flaps are brought together under pressure.

The lapping lateral and longitudinal edges of the weathering membranecan also be sealed by a mechanical clip as shown in FIG. 9. To adapt themembrane to the mechanical fastener shown in FIG. 9, the edge of themembrane opposite flap 36b is provided with a loose selvage portion 100.Clip 101 has a rounded upper surface 102 and intermediate section 103and a reversely bent lower lip 104. Clip 101 is continuous and is closedat end 105. Ribs 106, 107 and 108 extend longitudinally along one edgeof the clip and are adapted to engage one another when clip 101 is in aclosed position. Selvage is received between clip elements 102 and 103and flap portion 36b oppositely extends between clip elements 103 and104. Vertical projections 110 extend downwardly from intermediateelement 103 engaging opposite sides of the juncture between the planks.An additional projection 1 11 at end engages one of the planks. Fastener112 extends vertically between clip elements 102 and 103. In assembly ofthe clip, mastic or adhesive may be applied in ribs 106 and 107 to sealthe membrane to the clip. It will be obvious that as fastener 112 istightened and the clip compressed, the overlapping portions of themembrane will be sealed to the clip and the vertical projections on theunderside of the clip will be placed in tension to apply pressure to themembrane. One advantage of the clip arrangement is that any waterentering around fastener 1 12 does not penetrate the membrane but simplywill run out the end of the clip. The clip effects a sea] at 106, 107and 108 which allows the use of the fourway corner seal 21 to completelyweatherproof the membrane at the edge and comer junctures. The cornerseal is described in detail in the following paragraphs.

The present invention also makes provision for sealing the membrane inthe comer area of the planks. At the juncture of three or four planks, acomer area 118 is formed with a number of membrane sections overlyingone another. This is best seen in FIGS. 10 and 11. It will be noted thatthe common membrane corner area 118 is diagonally disposed from thecorner 16 formed between adjacent corresponding planks. A corner sealassembly generally designated by the numeral 21 seals the overlyingmembrane sections in the common corner area of planks. A flat metalbearing plate 120 underlies the overlying membrane section. Preferablyplate 120 is formed as an integral part of the plank structure tofacilitate assembly. The membrane flaps are lapped over lower plate 120.The opposite side of the corner joint is defined by generally convex capor disk member 125 having an annular lip portion 126. Mastic may beapplied around the periphery of the lip 126, A fastener 127 extendsthrough disk 125 into opposite bearing plate 120 and into subjacentplank c. Tightening of the mechanical fastener will draw the disk 125down, tightly compressing the membrane sections together between disk125 and plate 120 providing a watertight seal. The area of bearing plate120 and the area encompassed by the disk 125 should be large enough toprovide for any misalignment which might occur in the assembly of theplank sections.

FIG. 12 shows an alternate embodiment of the corner seal. Embodiment ofFIG. 12 is generally designated by the numeral 131 and includes flatbearing plate member 130 underlying the joint between adjacent plankmembers. Membrane flaps are lapped across plate 130. The upper side ofthe joint includes member 135 which has a center cup 136 with annularflange 137 projecting around the upper lip of the cup. Flange 137engages the surface of the outermost membrane and the inner end of cup136 contacts bearing plate member 130 through an appropriate cutout inthe membranes. Bearing plate 130 and joint member 135 are both of a heatconductive material. Once the joint is assembled, heat is applied tomember 135 within the cup 136. The substantial surface area of cup 136conducts heat to member 130 and serves to bond or vulcanize theoverlying layers of membrane to one another and to the joint members 130and 135. The vulcanization or bonding results in a secure weathertightseal.

FIG. 13 shows still another embodiment of the corner seal jointgenerally designated by the numeral 141. Joint 141 includes a bottombearing plate 140 formed as part of the plank at the membrane lap. Theupper joint member 145 includes a generally flat plate 146 supportingdownwardly projecting spikes or pins 147. The joint is formed by firstplacing bearing plate 140 in place and then lapping the adjacentmembrane sections over plate 140. Member 145 is then aligned over plate140 and pressure is applied to plate 146 to cause the spike members 147to pierce through the layers of the membrane until contact with bottomplate 140 is established. Members 140 and 145 are of a heat conductivematerial and the joint is sealed by application of heat to plate 146which is conducted by pins 147 to plate 140. This results in asubstantially uniform heating of the joint and the membranes in the areaof the joint, resulting in a vulcanized secure seal.

The present invention will be better understood from the followingdescription of assembly of a typical roof assembly using theconstruction planks of the present invention. A substructure comprisingprimary and secondary roof support members in the form of the lateralextending rafters 12 and longitudinally extending purlins 13 will beerected in place by a field construction crew. Once the substructure isin place the construction of the roof can proceed. It will be noted thatwhile the planks are described as being roof panels, it will be obviousthat the planks are adaptable for use as other construction sections orunits such as floors or load bearing or non-load bearing partitionmembers.

The construction crew will position the proper number of planks on thepurlins with the planks l5 transversely resting across the purlins asseen in FIG. 1. Generally the relationship of the length of the planksto the purlin spacing is such that the individual planks transverseseveral purlins having opposite plank ends 42 and 43 terminating above aflange 14 of the purlins. The planks are contiguously aligned in anend-to-end and side-by-side relationship with the complementary edgestructures in engagement. The adjacent longitudinal edges 40 and 41 ofthe planks are secured together by fasteners 60 extending throughoverlapping sections 48 and 53 of the panel 24 at locations intermediatethe purlins. To further increase the lateral strength of the sectionsand to resist applied stresses induced by wind loadings, tension membersare then secured in place. This is done by securing Z-clip 78 in placeover the subjacent purlin 13 by means of fastener extending throughlower leg 79 of the clip. Adjacent ends 71 and 72 of thetension strap 70are secured together by fastener 74 and pulled tight to place tension onthe members extending across the panels. Spacer 65 between the strapsand the panel section 48 gives adequate support to the fastener to allowthe fastener to start through the metal at the desired location. As thefastener penetrates the metal, the head of the fastener pulls the strap70 in tension and compresses the foam spacer 65. In the compressedcondition, spacer 65 serves to seal around the fastener as well asreduce heat transfer between the panel 24 and the tension member 70.

The inclusion of the straps is an important factor in the constructionof a roof or other section where the plank loading tends to separate theplanks from their support structure. The straps extends laterally acrossthe roof, being attached to the support structure only at the plankedges. All necessary fasteners can be secured from the top andintermediate fasteners extending through the planks are not required.Thus potential sources of leakage are eliminated and field assembly isexpedited.

The lateral edges 42 and 43 of abutting planks are simply placed inengagement forming a shiplap joint as seen in FIG. 4. As explained.above, the end joint is preferably located immediately above the purlinsto provide support for the joint.

Once the planks are in place, the weatherproof membrane 20 can besealed. End flap 36 is overlayed on the next adjacent panel. Fastenerassembly 86 carried on the marginal portion of the membranes is securedby applying force to one of the fastener members 86 or 88 to engage thefastener members in coacting relationship. This can be done by simplyapplying manual force to the upper surface of member 86 or theinterlocking portion may be fastened together by progressively matingthe sheets with a slide fastener so that the projections of one of thesheets fits into the channel of the other. The concurrent application ofa bonding or adhesive agent may be included when the fastener sectionsare engaged. Edge flap sections 37 are secured in place in similarfashion with the fasteners engaged.

Alternately the overlying end and edge seal flaps 36 and 37 can besealed to the adjacent marginal membrane portion by application of heatto obtain a seal. With this method, a source of heat such as a flat ironor blower emitting hot air will be run along the overlapping flap. Thetemperature must be at least the melting point or vulcanization point ofthe membrane material. Heat is applied to the top side of the overlapand causes the top layer of the membrane to melt or partially melt toform a bond between the members. Application of pressure immediatelyfollowing application of heat will compress the joint and further ensurethe integrity of the joint.

Once four contiguous planks have been placed with the membrane edgessealed, membrane corner seal 21 can be completed. Disk 125 is placed onthe top membrane layer above lower plate 120. Fastener 127 is driventhrough member 125 and into lower plate 120 causing the intermediateoverlying membrane layers to be compressed together tightly sealing thecorner. Factory applied mastic at lip 126 will further serve to seal thecorner. Any misalignment of planks occurring during assembly can beaccommodated and taken up at the corner seal. As explained above in afurther aspect of the present invention, the corner seal may include thestep of vulcanizing the overlaying membrane portions together. Heatapplied to the exterior member 125 is conducted to the lower bearingplate 120 causing the membrane layers to vulcanize to one another and tothe comer seal structure. The assembly of the roof system continuessubstantially as described until the entire roof is completed.

The plank can be formed into a roof section with relative speed ascompared to former built-up roof systems. A roof system using the basicplank structure can be installed in a wide range of weather conditions.Ambient temperature is not critical as with application of bitumen.Because of the modular nature of the plank, the plank can be placed anderected quickly to enclose the building in a minimum of time allowingcrews to complete interior work in a protected environment.

The plank, because of its structural design, provides a smooth hardsurface which is very resistant to exterior damage from foot traffic,weather and vibration. With the increased trend toward roof mountedaccessories, foot traffic is an increased problem. The uniquecombination of materials of the present plank provides a hard walkingsurface directly under the weather resistant membrane where it is mostneeded to support the membrane. The plank is also particularly adaptablefor use with a wide variety of accessories. The panel can be cut, sawedor bored to accept various fittings and accessories such as windows,ventilators, or conduits for electrical or mechanical accessories.

Other advantages to the present system reside in the compositeconstruction of the plank element. The insulation panel is placed overthe primary structural member rather than under it so as to minimize theexpansion and contraction of the primary structural element. Thisconfiguration also helps to spread concentrated loads over a wider partof the roof element thus reducing the possibility of localized rooffailure. The inner wall panel may be used with no additional interiortreatment as a wall surface presenting an aesthetically pleasingconstruction. Another advantage of the roof plank of the presentinvention is that the vapor barrier, which is generally defined by thecorrugated panel 29, can be located on the interior or the hot side ofthe panel. This way damaging and deteriorating condensation within theplank interior is avoided.

The fire resistance of the roof plank is also particularly good sincethe composite materials are low flammable or not flammable. Further,application of asphalt or flammable or toxic material is not required inthe construction. It is known that build-up roofs present a fire hazardsince the asphalt surface, when heated by fire, can generate gaseouscombustible fumes which contribute to the spread of fire.

Because of its good structural and fire resistant characteristics thepanel of the present invention lends itself to use in the constructionof a floor or wall on other construction units. FIG. 14 illustrates across sectional view of a modification of the invention adapted for useas a vertical firewall structure. The embodiment of FIG. 14 is generallydesignated by the numeral 150. The basic core structure of the plank issimilar to that described with reference to FIG. 3 and includesintermediate corrugated panel 27a enclosed on one side by interior sheetmember 30a and on the other by insulation 32a and exterior sheet 340.Panel 27a can be corrugated in a wide variety of shapes. Spacers 29a andreinforcing member 28a extend longitudinally within plank 150.Preferably spacers 28a and 29a are of a fire resistant material such asgypsum or a foamed plastic. Opposite edges structures 40a and 41a areconfigurated for lapping engagement with reference to the previouslydescribed embodiment. Similarly, the opposite lateral edges may beadapted to abbut in a lap joint if the height of the wall exceeds thelength of a panel. For most installations the plank ends will be squaredas the typical wall will not require vertically stacking the planks 150.

Panel 30a on the interior of the plank is wallboard or a similarmaterial having a good fire rating. An interior treatment such as avinyl or paper 151 covers the interior side of panel 30a. Panel 34a maybe plywood or a hardboard or similar composite material.

The exterior surface of upper panel 34a is weatherized with a covering153. Covering 153 protects the plank and also is selected to give thedesired exterior surface appearance such as aluminum, painted steel orsimulated stone.

To form a firewall structure, the wall panels are vertically alignedwith edges 40a and 41a lapping and secured with fasteners 60apenetrating into reinforcing members 28a as seen in FIG. 15. Fasteners80a project into appropriately spaced vertical structural members 156.The crevice between the panel edges is filled with a butyl caulkingcompound or the equivalent.

The advantages to such a fabricated wall structure are many. Lessfoundation is required because the weight of the planks is substantiallyless than the equivalent structure of concrete or block. The prefinishedexterior and interior permits fast installation and elimi-' nates needfor additional work. The components of the plank, all beingnon-flammable or fire resistant, result in a structure with a goodU-factor. and resultant reduction in building and insurance costs.

Thus the present invention provides a construction section which can beused as a basic element of a roof, or other construction unit. The basicplank is a particularly good structural member because it incorporatesfeatures which give it both good longitudinal and lateral strength. Usedas a roof deck, the transversely extending tension strap members serveto resist upward loading on roof due to reduced pressures at the outerroof surface because of wind. As a wall component, the plank can beprefinished at the interior and exterior surfaces. Factory assembly ofthe plank allows minimum labor cost and provides maximum quality controlresulting in more economical product with fewer field maintenanceproblems. The plank is highly versatile and allows substantial varianceof construction to meet various end needs such as strength, weight,thickness, fire characteristics and thermal conductivity.

It will be obvious to those skilled in the art to make modifications andchanges to the panels of the present invention. For example, it will beobvious to substitute other structural elements for the interior panelmember such as aluminum or fiberglass sheeting. Similarly, various formsof insulation and interior and exterior panels can be used. The membranemay similarly be of a wide variety of natural or synthetic materials toprovide the desired weather and waterproof exterior. To the extent thatthese changes and modifications do not depart from the spirit and scopeof the present invention they are intended to be encompassed therein.

What is claimed is:

l. A method of roof construction comprising:

erecting a roof supporting substructure;

arranging a multiplicity of prefabricated roof planks each carrying anintegral membrane sheet on said substructure in aligned contiguousrelationship to enclose said roof;

secruing said planks together at their abutting edges and ends in alapping joint;

securing spaced apart transversely extending strap members across saidpanels to said substructure and pretensioning said straps;

sealing the membrane sheet carried on the planks one to another to sealthe roof; and

sealing the membrane comer areas adjacent abutting planks.

2. A method of roof construction comprising:

erecting a roof supporting substructure; arranging a multiplicity ofelongated, prefabricated panel members in contiguous relationship on theroof supporting substructure, the prefabricated panel members havingwaterproof upper surfaces and a flexible waterproof flap extending fromthe waterproof upper surface of at least one edge of each contiguouspair of edges of adjacent panel members, the flap being sealed along itslength to the waterproof surface of the panel member to which it isattached to form a continuation of the waterproof surface; mechanicallyfastening the opposite edges of the panel members to the underlyingsubstructure to resist upwardly directed wind loads on the panels bymeans of tension forces developed in the panel member between theopposite edges; and

positioning a flexible flap over the mechanically fastened edges andsealing the flexible flap to the adjacent panel member to form acontinuous watertight membrane between the watertight surfaces of theadjacent panel members along the contiguous edges of the panel members.

3. A method of roof construction comprising:

erecting a roof supporting substructure;

arranging a multiplicity of elongated, prefabricated panel members incontiguous relationship on the roof supporting substructure, theprefabricated panel members having waterproof upper surfaces and aflexible waterproof flap extending from the waterproof upper surface ofat least one edge of each contiguous pair of edges of adjacent panelmembers, the flap being sealed along its length to the waterproofsurface of the panel member to which it is attached to form acontinuation of the waterproof surface, and having one half of amechanically interlocking and sealing fastener, the other panel having amating half of the fastener sealed along its length to the waterproofsurface of the other of the adjacent panel members;

mechanically fastening the opposite edges of the panel members to theunderlying substructure to resist upwardly directed wind loads on thepanels by means of tension forces developed in the panel member; and

positioning a flexible flap over the mechanically fastened edges of thepanel members and mechanically engaging the halves of the fasteners toform a continuous watertight membrane between the watertight surfaces ofthe adjacent panel members along the contiguous edges of the panelmembers.

4. A method of roof construction comprising:

erecting a roof supporting substructure;

arranging a multiplicity of elongated, prefabricated panel members incontiguous relationship on the roof supporting substructure, theprefabricated panel members having a waterproof upper surface formed bya flexible waterproof membrane adhered to a tension member having atransverse tensil strength, the membrane extending beyond at least oneedge of each contiguous pair of edges of adjacent panel members to forma flap;

mechanically fastening the opposite edges of the tension members of thepanel to the underlying substructure to resist upwardly directed windloads on the panels by means of transverse tension forces developed inthe tension member between the fastened edges; and

positioning a flexible flap over the mechanically fastened edges of thetension member and sealing the flexible flap to the membrane of theadjacent panel member to form a continuous watertight membrane.

5. A method of roof construction comprising:

erecting a roof supporting substructure including a plurality of spaced,parallel beam members;

arranging a multiplicity of rectangular, prefabricated panel members incontiguous relationship on the beam members with the panel membersdisposed transversely of and spanning a plurality of beam members, theprefabricated panel members having waterproof upper surfaces and aflexible waterproof flap extending from the waterproof upper surface ofat least one edge of each contiguous pair of edges of adjacent panelmembers, the flap being sealed along its length to the waterproofsurface of the panel member to which it is attached to form acontinuation of the waterproof surface;

mechanically fastening the opposite edges of the panel members to theunderlying beam members to resist upwardly directed wind loads on thepanels by means of tension forces developed within the panel member; and

positioning a flexible flap over the mechanically fastened edges andsealing the flexible flap to the adjacent panel member to form acontinuous watertight membrane between the watertight surfaces of theadjacent panel members along and over contiguous edges of the panelmembers which are fastened to the beam members.

6. A method of roof construction comprising:

erecting a roof supporting substructure including a plurality of spaced,parallel beam members;

arranging a multiplicity of rectangular, prefabricated panel members incontiguous relationship on the beam members with the panel membersdisposed transversely of and spanning a plurality of beam members, theprefabricated panel members having waterproof upper surfaces andflexible waterproof flaps extending from the waterproof upper surface ofat least one edge of each contiguous pair of edges of adjacent panelmembers, the flap being sealed along its length to the waterproofsurface of the panel member to which it is attached to form acontinuation of the waterproof surface and having one half of amechanically interlocking and sealing fastener, the other panel having amating half of the mechanically interlocking and sealing fastener sealedalong its length to the waterproof surface of the other of the adjacentpanel members;

mechanically fastening the opposite edges of the panel members to theunderlying beam members to resist upwardly directed wind loads on thepanels by means of tension forces developed within the panel member; and

positioning a flexible flap over the mechanically fastened edges of thepanel members and mechanically engaging the halves of the fasteners toform a continuous watertight membrane between the watertight surfaces ofthe adjacent panel members along and over contiguous edges of the panelmembers which are fastened to the beam members.

7. A method of roof construction comprising:

erecting a roof supporting substructure including a plurality of spaced,parallel beam members;

arranging a multiplicity of rectangular, prefabricated panel members incontiguous relationship on the beam members with the panel membersdisposed transversely of and spanning a plurality of beam members, theprefabricated panel members having a waterproof flexible membraneadhered over tension means extending transversely of the panel member,the membrane extending beyond at least one edge of each contiguous pairof edges of adjacent panel members to form a flexible flap;

mechanically fastening the tension means at opposite edges of the panelmembers to the underlying beam members to resist upwardly directed windloads on the panels at least partially by means of tension forcesdeveloped within the tension means; and

positioning a flexible flap over the mechanically fastened edges andsealing the flexible flap to the adjacent panel member to form acontinuous watertight membrane between the watertight surfaces of theadjacent panel members along and over contiguous edges of the panelmembers which are fastened to the beam members.

8. A method of roof construction comprising:

erecting a roof supporting substructure including a plurality of spaced,parallel beam members;

arranging a multiplicity of rectangular, prefabricated panel members incontiguous relationship on the beam members with the panel membersdisposed transversely of and spanning a plurality of beam members, theprefabricated panel members having a layer of insulation and at leastone thin sheet of tension material above the insulation, and a flexiblewaterproof membrane adhered over the upper surface of the-panel member,the membrane extending beyond at least one edge of each contiguous pairof edges of adjacent panel members to form a flexible flap;

mechanically fastening the panel member including the tension means atopposite edges of the panel members to the underlying beam members toresist upwardly directed wind loads on the panels at least partially bymeans of tension forces developed within the tension means; and

positioning a flexible flap over the mechanically fastened edges andsealing the flexible flap to the adjacent panel member to form acontinuous watertight membrane between the watertight surfaces of theadjacent panel members along and over contiguous edges of the panelmembers which are fastened to the beam members.

9. A method of roof construction comprising:

erecting a roof supporting substructure;

fabricating a multiplicity of panel members having waterproof uppersurfaces and a flexible waterproof flap extending from the waterproofupper surface from at least one edge of at least a portion of the panelmembers, the flap being sealed along its length to the waterproofsurface of the panel member to which it is attached to form acontinuation of the waterproof surface;

arranging the multiplicity of panel members in contiguous relationshipon the roof supporting structure with at least one flap provided foreach pair of contiguous edges;

mechanically fastening the opposite edges of the panel members to theunderlying substructure to resist upwardly directed wind loads on thepanels by means of tension forces developed in the panel member; and

positioning a flexible flap over the mechanically fastened edges andsealing the flexible flap to the adjacent panel member to form acontinuous watertight membrane between the watertight surfaces of theadjacent panel members along the contiguous edges of the panel members.

'UNITED STATES PATENT OFFICE CERTEFICATE OF CORRECTION PATENT NO.3,914,916

DATED October 28, 1975 INVENTOR( 1 Harold Graves Simpson, WarrenElsworth Scruggs, Richard Clark l N m D l R'c It IS certlfl d t af r rbrag6ear s ln tl?e 0 e-| ler%|f|ed patent and tnat sald Letters Patent arehereby corrected as shown below:

Column 1, line 38, "trafiice" should be --trafiic-.

(olumn 3, line 37, after "one" delete -of-.

Column 5, line 55, between "and" and "55 insert --member--.

Column 7, line ll, add at end of sentence.

Column 7, line 24, "The" should be --The--.

Column l2, line 33, "abbut" should be --abut--.

Column 14, line 34, between "having" and "transverse" delete --a-.

gigned and Stalcd this thirteenth Day of April1976 [SEAL] A lies I:

RUTH C. MASON C. MARSHALL DANN A Nesting Officer (ummissiuneruj'larer'zrs and Trademarks

1. A method of roof construction comprising: erecting a roof supportingsubstructure; arranging a multiplicity of prefabricated roof planks eachcarrying an integral membrane sheet on said substructure in alignedcontiguous relationship to enclose said roof; secruing said plankstogether at their abutting edges and ends in a lapping joint; securingspaced apart transversely extending strap members across said panels tosaid substructure and pretensioning said straps; sealing the membranesheet carried on the planks one to another to seal the roof; and sealingthe membrane corner areas adjacent abutting planks.
 2. A method of roofconstruction comprising: erecting a roof supporting substructure;arranging a multiplicity of elongated, prefabricated panel members incontiguous relationship on the roof supporting substructure, theprefabricated panel members having waterproof upper surfaces and aflexible waterproof flap extending from the waterproof upper surface ofat least one edge of each contiguous pair of edges of adjacent panelmembers, the flap being sealed along its length to the waterproofsurface of the panel member to which it is attached to form acontinuation of the waterproof surface; mechanically fastening theopposite edges of the panel members to the underlying substructure toresist upwardly directed wind loads on the panels by means of tensionforces developed in the panel member between the opposite edges; andpositioning a flexible flap over the mechanically fastened edges andsealing the flexible flap to the adjacent panel member to form acontinuous watertight membrane between the watertight surfaces of theadjacent panel members along the contiguous edges of the panel members.3. A method of roof construction comprising: erecting a roof supportingsubstructuRe; arranging a multiplicity of elongated, prefabricated panelmembers in contiguous relationship on the roof supporting substructure,the prefabricated panel members having waterproof upper surfaces and aflexible waterproof flap extending from the waterproof upper surface ofat least one edge of each contiguous pair of edges of adjacent panelmembers, the flap being sealed along its length to the waterproofsurface of the panel member to which it is attached to form acontinuation of the waterproof surface, and having one half of amechanically interlocking and sealing fastener, the other panel having amating half of the fastener sealed along its length to the waterproofsurface of the other of the adjacent panel members; mechanicallyfastening the opposite edges of the panel members to the underlyingsubstructure to resist upwardly directed wind loads on the panels bymeans of tension forces developed in the panel member; and positioning aflexible flap over the mechanically fastened edges of the panel membersand mechanically engaging the halves of the fasteners to form acontinuous watertight membrane between the watertight surfaces of theadjacent panel members along the contiguous edges of the panel members.4. A method of roof construction comprising: erecting a roof supportingsubstructure; arranging a multiplicity of elongated, prefabricated panelmembers in contiguous relationship on the roof supporting substructure,the prefabricated panel members having a waterproof upper surface formedby a flexible waterproof membrane adhered to a tension member having atransverse tensil strength, the membrane extending beyond at least oneedge of each contiguous pair of edges of adjacent panel members to forma flap; mechanically fastening the opposite edges of the tension membersof the panel to the underlying substructure to resist upwardly directedwind loads on the panels by means of transverse tension forces developedin the tension member between the fastened edges; and positioning aflexible flap over the mechanically fastened edges of the tension memberand sealing the flexible flap to the membrane of the adjacent panelmember to form a continuous watertight membrane.
 5. A method of roofconstruction comprising: erecting a roof supporting substructureincluding a plurality of spaced, parallel beam members; arranging amultiplicity of rectangular, prefabricated panel members in contiguousrelationship on the beam members with the panel members disposedtransversely of and spanning a plurality of beam members, theprefabricated panel members having waterproof upper surfaces and aflexible waterproof flap extending from the waterproof upper surface ofat least one edge of each contiguous pair of edges of adjacent panelmembers, the flap being sealed along its length to the waterproofsurface of the panel member to which it is attached to form acontinuation of the waterproof surface; mechanically fastening theopposite edges of the panel members to the underlying beam members toresist upwardly directed wind loads on the panels by means of tensionforces developed within the panel member; and positioning a flexibleflap over the mechanically fastened edges and sealing the flexible flapto the adjacent panel member to form a continuous watertight membranebetween the watertight surfaces of the adjacent panel members along andover contiguous edges of the panel members which are fastened to thebeam members.
 6. A method of roof construction comprising: erecting aroof supporting substructure including a plurality of spaced, parallelbeam members; arranging a multiplicity of rectangular, prefabricatedpanel members in contiguous relationship on the beam members with thepanel members disposed transversely of and spanning a plurality of beammembers, the prefabricated panel members having waterproof uppersurfaces and flexible waterproof flaps extending from the waterproofupper surface of at least oNe edge of each contiguous pair of edges ofadjacent panel members, the flap being sealed along its length to thewaterproof surface of the panel member to which it is attached to form acontinuation of the waterproof surface and having one half of amechanically interlocking and sealing fastener, the other panel having amating half of the mechanically interlocking and sealing fastener sealedalong its length to the waterproof surface of the other of the adjacentpanel members; mechanically fastening the opposite edges of the panelmembers to the underlying beam members to resist upwardly directed windloads on the panels by means of tension forces developed within thepanel member; and positioning a flexible flap over the mechanicallyfastened edges of the panel members and mechanically engaging the halvesof the fasteners to form a continuous watertight membrane between thewatertight surfaces of the adjacent panel members along and overcontiguous edges of the panel members which are fastened to the beammembers.
 7. A method of roof construction comprising: erecting a roofsupporting substructure including a plurality of spaced, parallel beammembers; arranging a multiplicity of rectangular, prefabricated panelmembers in contiguous relationship on the beam members with the panelmembers disposed transversely of and spanning a plurality of beammembers, the prefabricated panel members having a waterproof flexiblemembrane adhered over tension means extending transversely of the panelmember, the membrane extending beyond at least one edge of eachcontiguous pair of edges of adjacent panel members to form a flexibleflap; mechanically fastening the tension means at opposite edges of thepanel members to the underlying beam members to resist upwardly directedwind loads on the panels at least partially by means of tension forcesdeveloped within the tension means; and positioning a flexible flap overthe mechanically fastened edges and sealing the flexible flap to theadjacent panel member to form a continuous watertight membrane betweenthe watertight surfaces of the adjacent panel members along and overcontiguous edges of the panel members which are fastened to the beammembers.
 8. A method of roof construction comprising: erecting a roofsupporting substructure including a plurality of spaced, parallel beammembers; arranging a multiplicity of rectangular, prefabricated panelmembers in contiguous relationship on the beam members with the panelmembers disposed transversely of and spanning a plurality of beammembers, the prefabricated panel members having a layer of insulationand at least one thin sheet of tension material above the insulation,and a flexible waterproof membrane adhered over the upper surface of thepanel member, the membrane extending beyond at least one edge of eachcontiguous pair of edges of adjacent panel members to form a flexibleflap; mechanically fastening the panel member including the tensionmeans at opposite edges of the panel members to the underlying beammembers to resist upwardly directed wind loads on the panels at leastpartially by means of tension forces developed within the tension means;and positioning a flexible flap over the mechanically fastened edges andsealing the flexible flap to the adjacent panel member to form acontinuous watertight membrane between the watertight surfaces of theadjacent panel members along and over contiguous edges of the panelmembers which are fastened to the beam members.
 9. A method of roofconstruction comprising: erecting a roof supporting substructure;fabricating a multiplicity of panel members having waterproof uppersurfaces and a flexible waterproof flap extending from the waterproofupper surface from at least one edge of at least a portion of the panelmembers, the flap being sealed along its length to the waterproofsurface of the panel member to which it is attached to form acontinuation of the waterproof surface; arranging the multiplicity ofpanel members in contiguous relationship on the roof supportingstructure with at least one flap provided for each pair of contiguousedges; mechanically fastening the opposite edges of the panel members tothe underlying substructure to resist upwardly directed wind loads onthe panels by means of tension forces developed in the panel member; andpositioning a flexible flap over the mechanically fastened edges andsealing the flexible flap to the adjacent panel member to form acontinuous watertight membrane between the watertight surfaces of theadjacent panel members along the contiguous edges of the panel members.